Furnace.



M. W. SEWALL.

FURNAGE. APPLICATION FILED JUNE 1,1908..

Patented Nov. 30, 1909.

ATTUHVEY unirsi) STATES PA.

pk MINOTT W. SEWALI., 0F ROSELLE, NEW JERSEY, ASSIGNOR TO THE IBABCOCK & WL-

COX COMPANY, OF BAYONNE, NEW JERSEY, A CORPORATION 0F NEW JERSEY.

FURNACE.

Specification of Letters Patent.

Patented Nov. 30, 1909.

Application 1ed June 1, 1908. Serial No. 436,080.

To allwhom it may concern:

Be it known thatl, MINOTT W. SEWALL, a citizen of the United States, residing at Roselle, in the county of Union and State of New Jersey, have invented certain new and `useful Improvements in Furnaces, of which vand to provide means for preventing the formation of clinkers. I attain the former by forming a secondary combustion rchamber at or near the inner end of the grate and below the same, and the latter by providing means for causing an even and uniform sup` ply of air to pass through the entire fuel bed.' l/Vith the present methods large quantities of carbon are often found in the refuse and frequently an excess of air is introduced into the furnace to the detriment of economy in operation. The causes of the intro- 'duction of an excess of air in the furnace are numerous. One is the coking of the coal and then the cracking open of the crust of coke and the admission of air through the cracks while none passes through the body of the crusted surface. The fire lthus soon becomes ragged and lumpy, parts become thoroughly burned out and in other parts the coal is unconsumed and good coke passes on which is discharged with the ash and wasted.

Figure l of the accompanying drawing is a longitudinal section of a furnace provided with an ordinary mechanical Stoker of the chain-grate type having my improvements applied thereto. Fig. 2 is a transverse section on the plane of the line 2-2 of Fig. l.

The furnace to which my invention is applied may be of any usual or preferred construction in its general features of construction. That shown in the drawings is rep-- resented as provided with a mechanical Stoker, A, of the chain grate type.. The' grate is mounted upon and supported by sprocket wheels a', one of which may be driven by any suitable mechanism. The fuel is introduced into the furnace at the front through a hopper, and is delivered onto the grate, by which it is carried across the combustion chamber and toward the rear.

E indicates a pit or chamber into which the vash and unburned, or but partly consumed fuel is discharged from the grate. I t is situated below the rear end of the latter, and constitutes va secondary combustion chamber in which the remaining combustible constituents of thev fuel in what is delivered by the grate may be consumed and the products of combustion therefrom utilized. A transverse bridge wall or partition D -separates this chamber E from the main combustion chamber of the furnace. This wall is extended downward at the rear to form the rear curtain wall, b', of the coke and ash pit, behind which is a iue F leading to the combustion chamber of thefurnace. A doorway or a series of doorways or passages, F, are formed in the wall b', and constitutethe communications between the Vpit or chamber and the flue F. These openings F are at or near the bottom of the pit and are of such size, in vertical dimensions, thatthey become closed as soon as a small amount of material has been discharged by the grate. The chamber E has communication at the front with the air supply, the air passing through the hot grate bars, as

- indicated by the arrows at M, and at the rear communicates with the air-inducing means, as the stack, through the flue F', so that air is caused to pass downwardly through the mass of ash and unconsumed and burning fuel that gradually accumulates therein. The chain grate A provides means for automatically feeding fuel to the main combustion lchamber, and lfor feeding partially burned fuel to the secondary down draft combustion chamber.

A damper, G, is located in the Hue F', by which the latter is opened or closed as may be desired.

H H indicate dumping doors at the bottom of the chamber E, to permit theyremoval of the ashes therefrom.

The front wall of the secondary combustion chamber is inclined upward, extending from the dumping doors, yH, into .close proximity to the lower run of the cham Grate, as

indicated at This wall directs 1nto the,

secondary combustion chamber any pieces of unconsumed fuel that may fall through the wg form .of a water rear parts of the grate. The hot gases incident to the combustion taking place within thechamber E pass into the main combustion chamber of the furnace and there mingle with the hot products of combustion from the main fuel bed, and are conducted away for utilization. .Thus I not only consume the u'nburned parts of the f uel carried over the end of the grat but I utilize innnedi- ,o ately the heat incident to that combustion.

In order to prevent the formation of cracks or openings at the rear end of the grate, where the grate bars turn and the ash and unburned fuel are discharged, and there 5 by provide free passages for the air7 which naturally seeks such free openings, rather than to pass through the bed of fuel on the grate and to control the feed of fuel to the secondary down draft furnace. l. arrange a dam or retarding device near the rear end of the grate and a little above the upper plane thereof. Against this rretarding device, which is arranged transversely across the furnace, the upper layers yof the fuel are fed by the onward moving grate and caused to bank, thus elfectually closing the tire chamber at. the rear, and tending to maintain a uniform depth of fuel throughoutall portions of the furnace. I prefer that this retarding device or dam lshould be in the box B. This water box is the front or forward end of the wall D and the upper surface of the grate. By arranging the box .at this point the formation of clinlrers at the rear of the grate is largely prevented.

N indicates side wall water boXes arranged longitudinally of the furnace and having in'- let and outlet pipes n and n respectively. 40 I have shown these water boxes'as bearing directly against the grate. It is obvious, however, that a plate or a course of tire brick may intervene between the boxes and the grate. By this construction the air supplied to the grate is prevented from escaping at the sides thereof. The object of the water boxes is to prevent the formation of rvclinkers on the furnace walls and theden struction thereof caused by the `removal of such formation. p

It is .well known that the formation of clinkers on the side walls causes a disturb- 'v mounted between ance of the fuel bed, with the result that air holes or cracks are formed therein. This causes the escape of air to the combustion chamber which is detrimental to ,the economical operation vof the furnace and also causes the fuel to burn out in some parts, while leaving other parts unconsumed `as already described; t

It will beseen that in a'furnace, such as I have described no clinkers can form on the side and end Walls; also that the fuel bed is being continually packed at the rear end, with the result that there is a uniform sup- )ly of air to all parts of the fire; and that therefore better conditions of combustion are obtained.

rI"he extensioirof the chain grate into the secondary down draft furnace causes all air passing through the rear of the grateto pass either through the fuel on the grate or that in the secondary down draft furnace and thence to the main combustion chamber, thus providing means for a draft of air through the fuel in the secondary chamber and at the same time preventing any passage of excess air into the main combustion chamber through an effort to consumethefuel in the secondary chamber.

What I claim iszl. A furnace comprising a main combusf tion chamber, a secondary combustion chamber arranged to receive the unconsumed fuel from the formerav the furnace being provided with an independent flue for the gases from the secondary combustion chamber.

2. A furnace comprising a main combustion chamber, a secondary combustion chamber arranged to receive the unconsumed fuel from the former, and a wall separating the two chambers and spaced from the furnace wall, to form an independent flue for the gases from the secondary combustion chamber.

A furnace comprising a main combustion chamber, a secondary combustion chamber arranged to receive the unconspmed fuel from the former, a Wall separating the two chambers and spaced from the furnace wall to form an independent liuc for the gases ,from the secondary combustion chamber,

and a damper in said flue.

' 4. A furnace comprising a main combustion chamber a'secondary combustion chamber arranged below and receiving the unconsumed' fuel from the main chamber, a wall separating the twochambers and spaced from the furnace Wall to lform an independentiiue for the gases from the secondary combustion chamber whereby a down-draft of airffrom the main supply is provided for said secondary chamber.

5. A furnace comprising a main combus- Lion chamber, a secondary combustion cham ter chamber, a bottom wall for said secondary chamber extended upward and forwardv into close proximity to the lower /roof of the chain grate, and a Wall sepaa'cliain grate for feeding fuel through the former and discharging it into the latspaced from the furnace wall to form an independent Hue for the gases from the secondary chamber and to cause a down-draft main supply is provided for the secondary combustion chamber.

S. A furnace comprising a main combustion chamber, a secondary combustion chamber arranged to receive the unconsumed fuel from the former, a Water box dam to control the feedof fuel to said secondary chamber, water boxes at the sides of the grate for the purpose described, and alwall separating the two lchambers and spaced from the furnace wall to form an independentue for the gases from the secondary combustion chamber.

. M INOTT W. SEWALL. Witnesses:

R. B. CAVANAGH, W. A. PAULI-NG. 

